Manufacture of wires of magnesium or alloys thereof



Patente :ar. 7, 1939 MANUFACTURE OF WIRES OF MAGNES OR ALLOYS THEREOF Hans Hadenfeldt, Berlin, Germany, and Bernhard Blumenthal, New York, N. Y.

N Drawing. Application July 8, 1937, Serial No. 152,566. In Germany September 13, 1932 7 Claims.

The present invention relates to a process for the manufacture of magnesium or magnesium alloy wires of extremely small diameter by cold drawing. The applicationis a continuation-inpart of our application Serial No. 687,909, filed September 1, 1933 now Patent No. 2,094,578, issued October 5, 1937. By our process, wires of a diameter of less than 0.2 mm., and particularly of a diameter of about 0.04 to 0.06 to 0.1 mm. can

10 be manufactured.

We have found that these thin wires can be prepared by cold drawing in passes involving an extremely small reduction of diameter not exceeding about 20%, while subjecting the wire between each pass to a heat-treatment at a suitable annealing temperature. A temperature of 300 C.

. has been found to give 'the best results for most of the wires that we have tested. Lower temperatures may be employed and also somewha t' higher ones, but we have found that the lower The wires were subjected to a heat-treatment 35 after each single pass at an annealing temperature of 300 C. It will be seen that the decrease in.

cross-section for each of these passes varies from 10 to 19% and that the average decrease is about 15%.

It is not necessary to subject the wire to the heat-treatment after every pass. It is possible, for instance, to proceed without intermediate heating when substituting two passes, say from 0.22 to' 0.21 mm. and from 0.21 to 0.20 mm., for a 45 single pass of 0.22to 0.20 mm. It is also possible to work in somewhat greater passes than indicated in the example. For instance, we may proceed from 0.22 to 0.195 mm. in one pass or subdivide thispass into two or more sub-passes without 50 intermediate heating. It is essential, however, that the individual decreases produced by each pass be relatively small.

Nor is it necessary that we start with a wire of 0.30 mm, since a magnesium or magnesium alloy 55 wire of any diameter may be employed as the starting material, regardless of how that wire has been produced.

In order to avoid pickling which would ordinarily be necessary after heating, the heating is preferably effected with the exclusion of air, for instance, in an oil bath or in vacuo. The single wires, thus prepared, may be twisted or braided together to form ropes or cables in the customary manner, for instance, stranded with the lay to the left or with the lay to the right, twisted in an opposite direction or twisted in the same direction, or as cable-laid rope. The rope may be formed by twisting or braiding wires of the same orof different diameters, and the wires may be laid to strands and the strands to ropes.

The wires manufactured in accordance with our process are especially useful for use as sutures and ligature materials. When so used; these wires of extremely small cross-section are twisted together'in the form of ropes. Wires or ropes of magnesium or magnesium alloys can be rendered sterile without difiiculty by boiling in water and are easily resorbed by the body. The resorptionof the said wires proceeds so slowly that the purpose of the suture, that is closing of the wound, is attained. The wires or ropes of magnesium or magnesium alloys may also be used for the ligature of blood vessels.

Whenever the term magnesium alloy is used in the claims or elsewhere in this application, it is understood to include magnesium base alloys generally regardless of the particular'nature of the alloying metal or metals as long as they are capable of being worked.

While we have described our new process in great detail and with respect to preferred embodiments thereof ,we do not desire to limit ourselves to such details or embodiments. modifications and changes may be made without departing from the spirit or scope of the inven-= tion in its broadest aspects. Hence, we desire to cover all modifications and forms within the scope or language of any one or more of the appended claims. Furthermore, while we have developed the description of our process in its specific aspects on the basis of wires which have circular cross sections, it is understood that the Many process is applicable to wires of any cross-sec- 2. A process for the manufacture of magnesium and magnesium alloy wires of small diameter which comprises cold drawing the wire by passes which comprises cold drawing the wire by passes,

each efiecting a reduction in the diameter of the wire not exceeding 20%, frequently heat-treating the wire between individual passes at a temperature' of about 300 C. and repeating the drawing and heat-treating until a diameter of from 0.1

.to 0.04 mm. is attained.

5. A process for the manufacture of magnesium and magnesium alloy wires of small diameter aieaeae which comprises cold drawing the wire by passes, each effecting a reduction in the diameter of the wire not exceeding 20%, heat-treating the wire after each pass at a temperature of about 300 C., and repeating the drawing and heat-treating steps until the desired diameter is reached.

6. A process for the manufacture of. wires of magnesium and magnesium alloys which comprises colcl drawing the wire by passes, each effecting a reduction in cross-section of the wire between about 10 and about 20% and heat-treating the wire after each pass at a temperature of about 300 C. until the desired diameter is reached.

7. A process for the manufacture ofwires of magnesium and magnesium alloys which comprises cold drawing the wire by passes, each effecting a reduction in cross-section of the wire of about 15%, and heat-treating the wire after each pass at a temperature ofabout 300 C. until the desired diameter is reached.

HANS HADENFELDT. BERNHARD BLUMENTHAL. 

